Improvement in safety-valves



` i the county of Essex and State` of New Jersey, have 1 made certain Improvementsin SafetyValves, of which the following isa specification. l

The improvementrelates `to providing, `in one Aattaehmeutlto boilers, against `the two-fold contingencontinuously rendering iron and copper boilers at any` f i ,lo `meet .and obviatefthese dangers it requires a sired pressure, which `shallbe so'construeted as to be a of water or steam, yet shallfreely open and allow a free ingress of air whenever` that pressure is removed 1 combined in smalli space, all the parts easy of access "i" `For the pressure-gauge, ais a piston in a! Cylinder,

i spring, d, the lower end of the spring resting on thel i, piston a, and the upper end receiving the pressure of the'regnlating-screw cap @,through which the stem c v projects. i

j will@ lil5 i `srt;their c. MARSH, or

JNEWARK, NEW JERSEY.

i l Letters Patent No 112,611, dated March 14,1871.

IMPRovEMEN-r IN -sAFETv-vALvEs.

l The `Sehefiule referred to h1 these Letters Patent and paxt of the same.

" I, `STEWABIJO.` MARSH;-` of the ctyfof Newark, in

cies of explosion and collapse, to which neglect, carelessness,l1or other `and unavoidable circumstances are timeliable.

valve conveniently adjustable, at pleasure, to any de# safely and pcrfectlyyclosed y under pressure of a head bythe bcilerbeconing empty. l

Itis also desirable that the two features should be for adjustment, for repairing, or cleansing.` y

" Our mannerof meeting and satisfying these requirements is shown in the accompanyingl drawing, in which the parts in'their combinings areshown in views in section.

b, having? a guide-stem, c, around which iis* a sti Inffront of the valve-case is an escape-pipe, f, the `position of which is designated by; dotted circles in- One end of the cross-pipe below is connected with the boiler, and the other With a stop-cock. Wheny the steam forces the p'iston against the spring resistcourse there is an immediate relief.

For the ingress of air, when required, there is within the lower` end ofthe piston a valve, j, the stem of which slides in the guide-nut k.

Through the guide-nut lo there are apertures l, and also through the edges of the valve j thereA are holes, that are closed by the valve-seat when the valve is pressed and held up against it. Above the valve-seat is an opening, fm., with holes therefrom into the recess n, around the piston a.

When 'the piston is down toits resting-place andV the valve therein is also down, there is a free passage for air through the escape-pipe, piston, valve, and guide-nut into the boiler; but the moment there is a head-pressure.'of water in the boiler, the valve j rises toits seat and closes all the openings, preventing escape of water or steam until the piston is forced above the esc-apepipe provided for that purpose. What I claim and desire to secure .is- The piston a, cylinder b, spring d, valve j, and

l guide-uut It, all constructed, combined, and arranged as and for thepurpose hereinabove set forth.

STEWART O. MARSH. Witnesses:

W. M. Goonrive, EDWARD OOLLVEB.

Iig. 1, andthe pipefshown in a sectional `sideview in 

